Resiliently tiltable vehicle jack base

ABSTRACT

A resiliently tiltable load supporting base for vehicle jacks is described. The base has a ground engaging plate having a substantially flat bottom with upturned peripheral edges and a rounded depression in a central region of the bottom. A load receiving plate having a substantially flat top with down-turned peripheral edges is mounted within the ground engaging base. A generally spherical socket extends downwardly in a central region of the top of the load receiving plate and this socket has a generally flat bottom with a downwardly directed rounded projection which mates with the rounded depression in the ground engaging base. An elastomeric means, e.g. a hard rubber block, is mounted between the ground engaging base and the load receiving plate in a region between the central socket and downturned peripheral edges. This hard rubber is positioned on all sides of the socket and maintains the two parts of the base in paralled relationship while permitting some resilient tilting of a screwjack post and the load receiving plate with respect to the ground engaging member.

United States Patent [1 1 [111 3,881,692 Clarke 1 May 6, 1975 RESILIENTLY TILTABLE VEHICLE JACK [57] ABSTRACT BASE Inventor: Bernard S. Clarke, Orillia, Ontario,

Canada Assignee: Seeburn Metal Products Limited,

Beaverton, Ontario, Canada Filed: June 21, 1974 Appl. No.: 481,771

References Cited UNITED STATES PATENTS 6/1931 Kohler 254/101 6/1931 Larson et al 254/101 9/1938 Woodworth 254/101 FOREIGN PATENTS OR APPLICATIONS 7/1959 United Kingdom 254/101 3/1941 United Kingdom 254/DIG. l

Primary Examiner-Al Lawrence Smith Assistant Examiner-Robert C. Watson A resiliently tiltable load supporting base for vehicle jacks is described. The base has a ground engaging plate having a substantially flat bottom with upturned peripheral edges and a rounded depression in a central region of the bottom. A load receiving plate having a substantially flat top with down-turned peripheral edges is mounted within the ground engaging base. A generally spherical socket extends downwardly in a central region of the top of the load receiving plate and this socket has a generally flat bottom with a downwardly directed rounded projection which mates with the rounded depression in the ground engaging base. An elastomeric means, e.g. a hard rubber block, is mounted between the ground engaging base and the load receiving plate in a region between the central socket and downturned peripheral edges. This hard rubber is positioned on all sides of the socket and maintains the two parts of the base in paralled relationship while permitting some resilient tilting of a screwjack post and the load receiving plate with respect to the ground engaging member.

5 Claims, 5 Drawing Figures RESILIENTLY TILTABLE VEHICLE JACK BASE This invention relates to a resiliently tiltable load supporting base .for vehicle jacks.

The mechanical advantage of vehicle jacks is usually obtained by screw, lever or hydraulic action. Thus, the screw jack has a threaded screw fitted to a gear wheel which is a part of the base of the jack. This gear wheel engages a pinion gear which is manually turned by means of a handle or crank. The screw jack is widely used as a light weight vehicle jack.

The jack is usually mounted on a flat floor or ground engaging base with the post of the jack mounted perpendicularly to this base. One difficulty that has been encountered with the usual jack of the above type is that the support surface is not always level and this may result in jamming of the elevating portion of the jack within the encasing elevator tube.

It is the object of this invention to provide a novel resiliently tiltable base which can compensate for these irregularities and thereby prevent any tendancy for binding within the elevator tube.

Thus, in accordance with the present invention there is provided a resiliently tiltable load supporting base for vehicle jacks. It comprises an outer metallic base having a substantially flat bottom for engaging the ground or floor with upturned peripheral edges and a rounded depression in a central region of the bottom. Mounted within this space is an inner metallic load receiving plate having a substantially flat top with downturned peripheral edges. A socket extends downwardly in the central region of the top and this socket is adapted to receive a jack tube and also has in the bottom thereof a downwardly directed rounded projection which mates with the rounded depression in the outer base member. Also mounted between the outer base member and the inner load receiving plate in the region between the central socket and the downturned peripheral edges is an elastomeric slab means which urges the outer base member and inner plate into parallel relationship. Thus, the inner load receiving plate is resiliently tiltable with respect to the outer base member along a substantially horizontal axis.

According to a preferred embodiment, the outer base member is of a rectangular configuration and has a rounded, upwardly projecting ridge extending along a central axis, this ridge being bifurcated at a central region to form a central dish-shaped depression. This is the abovementioned depresion which mates with the projection on the bottom of the socket in the inner load receiving plate. The load receiving plate is also preferably rectangular with the peripheral edges terminating in a narrow peripheral flange. This flange preferably has downwardly directed, rounded projections in midpoints of opposite ends such that they rest on the ridge of the outer base member, thereby permitting rocking only on one horizontal axis.

The elastomeric slab means is preferably in the form of a hard synthetic or natural rubber block or blocks, e.g. of 60 to 70 durometer hardness. For convenience, four such blocks can be used, these being positioned adjacent the four corners of the load receiving plate.

The base according to this invention can be adapted for use with any kind of vehicle jack but is particularly well adapted for use with the usual screw jack having an elevator screw engaging a gear wheel mounted on a vertical axis in the lower end of a jack elevator tube.

With this arrangement a bearing support for the gear wheel is mounted in the socket of the load receiving plate.

constructional forms of the invention will now be described, but way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a side elevation in partial section showing details of the jack base of the invention;

FIG. 2 is an end elevation in partial section;

FIG. 3 is a plan view of the base only;

FIG. 4 is a sectional view of the base only; and

FIG. 5' is an end elevation of the entire jack as it appears on uneven ground.

Referring now particularly to FIG. 1, it will be seen that the jack portion has a tubular outer casing 10 in the form of two semicylindrical halves joined by flanges 11. These flanges 11 are spot-welded together.

Within this case 10 is an elevator tube 12 which can typically be cold drawn seamless mechanical steel and a cap member 12a is mounted on the top end of tube 12. Mounted on cap 12a is a substantially U-shaped load support 13 and this load support is rotatably mounted on the cap by a central pivot.

The internal mechanism of the jack structure has not been shown in detail but it includes the usual components of a typical screw jack assembly including a sleeve 37, the elevator tube 12, elevator screw 14 and a central drive screw, details of which are not shown. The screw mechanisms are rotated by way of gear member 15 having gear teeth 15a and supported by annular flange member 36 within a bearing member 18. The gear member 15 is in turn driven by pinion gear 16 having teeth 17 which mesh with the gear teeth 15a. The outer end of pinion gear 16 has a slot 40 for receiving a handle. The pinion gear 16 is mounted within a friction bearing 35 which can conveniently be of a material such as that available under the trademark DERLIN.

Looking now at the base of the jack, it will be seen that this includes an outer member 19 and an inner member 26. The outer member 19 has a ground engaging flat bottom portion 20 and upturned peripheral side edges 21 and upturned peripheral end edges 22, these upturned edges being joined by a rounded corners as can be seen from FIG. 3.

Extending along the length of plate 20 in a central region is an upwardly projecting rounded ridge 23. As can be seen from the broken lines in FIG. 3, this ridge is bifurcated in a central region, forming a pair of semicircular portions 24. Within these semi-circular portions 24 is a dish-shaped depression 25 serving as a bearing support.

The inner base member 26 has upper flat base portions 41 which peripherally merge into downwardly inclined edge portions 28 which finally merge into narrow flat peripheral edge flange 27. Downwardly projecting ridge portions 29 are formed in the end flanges 27 and 28 and these can be seen in the best detail in FIG. 4. These downwardly directed projections 29 rest upon the upwardly projecting ridge 23 in plate 20 providing a pivot point between the two plates.

In a central region of base plate 26 is a downwardly pressed cylindrical socket having side walls 31 and a substantially flat bottom 32. In a central region of the bottom 32 is a rounded depression 33 which mates with the dish-shaped depression in the central region of plate 20. The socket 30 serves as the main holding and support portion for the jack cylinder and these dish portions 25 and 33 serve as a pivotal direct contact between the two plates.

Holes 38 are provided in plate 26 and the jack portion is rigidly fixed to the plate 26 by way of rivets 39 extending through the holes 38.

Mounted within the gap formed between the inclined flanges 28 and the socket 30 of inner plate member 26 are four rubber blocks 34. These rubber blocks 34 completely fill the vertical space between plates 19 and 26 as can be seen from FIGS. 1 and 2 so that the rubber blocks tend to hold these plates in a parallel relationship. However, when the jack is mounted on an irregular floor or uneven ground, it will be seen from FIG. that the jack cylinder portion can tilt with respect to the base by compressing one of the rubber blocks 34. Of course, since these rubber blocks are quite hard, eg 60 to 70 durometer hardness, it will be seen that a considerable load is necessary before this tilting occurs and the degree of tilt is limited by the length of the side flanges 28. When the load on the jack is released, the resiliency of the rubber blocks causes the plates 19 and 26 to return from the position shown in FIG. 5 to the position shown in FIG. 2.

The embodiments of the invention in which an exclusive property or privelege is claimed are defined as follows:

l. A resiliently tiltable load supporting base for vehicle jacks, comprising (a) a rectangular metallic base member having a substantially flat bottom with upturned peripheral edges and a rounded ridge extending along a central axis thereof, said ridge being bifurcated at a central region to form a central dish-shaped depression in said bottom, (b) a metallic load receiving plate having a substantially flat top with downturned peripheral edges terminating in a narrow peripheral flange, said flange having downwardly directed, rounded projections in mid-points of opposite ends, said projections being adapted to rest on said base member ridge and a socket extending downwardly in a central region of said top, said socket being adapted to receive a jack tube and having in the bottom thereof a downwardly directed rounded projection which mates with said dish-shaped depression in the base member and (c) elastomeric slab means mounted between said base member and load receiving plate in a region between the central socket and downturned peripheral edges, whereby the load receiving plate is resiliently tiltable with respect to the base member along a substantially horizontal axis.

2. A device according to claim 1 wherein the socket is substantially cylindrical with a flat bottom having a downwardly directed central, dish-shaped projection.

3. A device according to claim 1 wherein said elastomeric slab means comprises hard synthetic or natural rubber blocks.

4. A device according to claim 3 wherein four elastomeric blocks are positioned at four corners beneath said load receiving plate.

5. A device according to claim 1 having a screw jack post mounted in said socket. 

1. A resiliently tiltable load supporting base for vehicle jacks, comprising (a) a rectangular metallic base member having a substantially flat bottom with upturned peripheral edges and a rounded ridge extending along a central axis thereof, said ridge being bifurcated at a central region to form a central dishshaped depression in said bottom, (b) a metallic load receiving plate having a substantially flat top with downturned peripheral edges terminating in a narrow peripheral flange, said flange having downwardly directed, rounded projections in mid-points of opposite ends, said projections being adapted to rest on said base member ridge and a socket extending downwardly in a central region of said top, said socket being adapted to receive a jack tube and having in the bottom thereof a downwardly directed rounded projection which mates with said dish-shaped depression in the base member and (c) elastomeric slab means mounted between said base member and load receiving plate in a region between the central socket and downturned peripheral edges, whereby the load receiving plate is resiliently tiltable with respect to the base member along a substantially horizontal axis.
 2. A device according to claim 1 wherein the socket is substantially cylindrical with a flat bottom having a downwardly directed central, dish-shaped projection.
 3. A device according to claim 1 wherein said elastomeric slab means comprises hard synthetic or natural rubber blocks.
 4. A device according to claim 3 wherein four elastomeric blocks are positioned at four corners beneath said load receiving plate.
 5. A device according to claim 1 having a screw jack post mounted in said socket. 